Question

Why can’t the following argument be made against the claim that primitive types are immutable in Javascript:

var $b = false;
$b = true;
alert($b); //-> true

I am misunderstanding what it means for a variable to immutable.

Answer 1

Values are immutable; variables are not.

$b = true changes $b to contain the true value.
The immutable false value is not changed.

Some languages support immutable variables as well (C++’s const, Java’s final, or C#’s readonly); Javascript does not.